Commit | Line | Data |
---|---|---|
7ed49443 JB |
1 | /* Abstraction of GNU v3 abi. |
2 | Contributed by Jim Blandy <jimb@redhat.com> | |
451fbdda | 3 | |
4c38e0a4 | 4 | Copyright (C) 2001, 2002, 2003, 2005, 2006, 2007, 2008, 2009, 2010 |
0d5de010 | 5 | Free Software Foundation, Inc. |
7ed49443 JB |
6 | |
7 | This file is part of GDB. | |
8 | ||
a9762ec7 JB |
9 | This program is free software; you can redistribute it and/or modify |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 3 of the License, or | |
12 | (at your option) any later version. | |
7ed49443 JB |
13 | |
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
7ed49443 JB |
21 | |
22 | #include "defs.h" | |
23 | #include "value.h" | |
24 | #include "cp-abi.h" | |
362ff856 | 25 | #include "cp-support.h" |
7ed49443 | 26 | #include "demangle.h" |
b18be20d | 27 | #include "objfiles.h" |
0d5de010 DJ |
28 | #include "valprint.h" |
29 | ||
3d499020 | 30 | #include "gdb_assert.h" |
5f8a3188 | 31 | #include "gdb_string.h" |
7ed49443 | 32 | |
b27b8843 | 33 | static struct cp_abi_ops gnu_v3_abi_ops; |
7ed49443 JB |
34 | |
35 | static int | |
36 | gnuv3_is_vtable_name (const char *name) | |
37 | { | |
38 | return strncmp (name, "_ZTV", 4) == 0; | |
39 | } | |
40 | ||
41 | static int | |
42 | gnuv3_is_operator_name (const char *name) | |
43 | { | |
44 | return strncmp (name, "operator", 8) == 0; | |
45 | } | |
46 | ||
47 | ||
48 | /* To help us find the components of a vtable, we build ourselves a | |
49 | GDB type object representing the vtable structure. Following the | |
50 | V3 ABI, it goes something like this: | |
51 | ||
52 | struct gdb_gnu_v3_abi_vtable { | |
53 | ||
54 | / * An array of virtual call and virtual base offsets. The real | |
55 | length of this array depends on the class hierarchy; we use | |
56 | negative subscripts to access the elements. Yucky, but | |
57 | better than the alternatives. * / | |
58 | ptrdiff_t vcall_and_vbase_offsets[0]; | |
59 | ||
60 | / * The offset from a virtual pointer referring to this table | |
61 | to the top of the complete object. * / | |
62 | ptrdiff_t offset_to_top; | |
63 | ||
64 | / * The type_info pointer for this class. This is really a | |
65 | std::type_info *, but GDB doesn't really look at the | |
66 | type_info object itself, so we don't bother to get the type | |
67 | exactly right. * / | |
68 | void *type_info; | |
69 | ||
70 | / * Virtual table pointers in objects point here. * / | |
71 | ||
72 | / * Virtual function pointers. Like the vcall/vbase array, the | |
73 | real length of this table depends on the class hierarchy. * / | |
74 | void (*virtual_functions[0]) (); | |
75 | ||
76 | }; | |
77 | ||
78 | The catch, of course, is that the exact layout of this table | |
79 | depends on the ABI --- word size, endianness, alignment, etc. So | |
80 | the GDB type object is actually a per-architecture kind of thing. | |
81 | ||
82 | vtable_type_gdbarch_data is a gdbarch per-architecture data pointer | |
83 | which refers to the struct type * for this structure, laid out | |
84 | appropriately for the architecture. */ | |
b27b8843 | 85 | static struct gdbarch_data *vtable_type_gdbarch_data; |
7ed49443 JB |
86 | |
87 | ||
88 | /* Human-readable names for the numbers of the fields above. */ | |
89 | enum { | |
90 | vtable_field_vcall_and_vbase_offsets, | |
91 | vtable_field_offset_to_top, | |
92 | vtable_field_type_info, | |
93 | vtable_field_virtual_functions | |
94 | }; | |
95 | ||
96 | ||
97 | /* Return a GDB type representing `struct gdb_gnu_v3_abi_vtable', | |
98 | described above, laid out appropriately for ARCH. | |
99 | ||
100 | We use this function as the gdbarch per-architecture data | |
9970f04b | 101 | initialization function. */ |
7ed49443 JB |
102 | static void * |
103 | build_gdb_vtable_type (struct gdbarch *arch) | |
104 | { | |
105 | struct type *t; | |
106 | struct field *field_list, *field; | |
107 | int offset; | |
108 | ||
109 | struct type *void_ptr_type | |
fde6c819 | 110 | = builtin_type (arch)->builtin_data_ptr; |
7ed49443 | 111 | struct type *ptr_to_void_fn_type |
fde6c819 | 112 | = builtin_type (arch)->builtin_func_ptr; |
7ed49443 JB |
113 | |
114 | /* ARCH can't give us the true ptrdiff_t type, so we guess. */ | |
115 | struct type *ptrdiff_type | |
e9bb382b | 116 | = arch_integer_type (arch, gdbarch_ptr_bit (arch), 0, "ptrdiff_t"); |
7ed49443 JB |
117 | |
118 | /* We assume no padding is necessary, since GDB doesn't know | |
119 | anything about alignment at the moment. If this assumption bites | |
120 | us, we should add a gdbarch method which, given a type, returns | |
121 | the alignment that type requires, and then use that here. */ | |
122 | ||
123 | /* Build the field list. */ | |
124 | field_list = xmalloc (sizeof (struct field [4])); | |
125 | memset (field_list, 0, sizeof (struct field [4])); | |
126 | field = &field_list[0]; | |
127 | offset = 0; | |
128 | ||
129 | /* ptrdiff_t vcall_and_vbase_offsets[0]; */ | |
130 | FIELD_NAME (*field) = "vcall_and_vbase_offsets"; | |
e3506a9f | 131 | FIELD_TYPE (*field) = lookup_array_range_type (ptrdiff_type, 0, -1); |
7ed49443 JB |
132 | FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; |
133 | offset += TYPE_LENGTH (FIELD_TYPE (*field)); | |
134 | field++; | |
135 | ||
136 | /* ptrdiff_t offset_to_top; */ | |
137 | FIELD_NAME (*field) = "offset_to_top"; | |
138 | FIELD_TYPE (*field) = ptrdiff_type; | |
139 | FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; | |
140 | offset += TYPE_LENGTH (FIELD_TYPE (*field)); | |
141 | field++; | |
142 | ||
143 | /* void *type_info; */ | |
144 | FIELD_NAME (*field) = "type_info"; | |
145 | FIELD_TYPE (*field) = void_ptr_type; | |
146 | FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; | |
147 | offset += TYPE_LENGTH (FIELD_TYPE (*field)); | |
148 | field++; | |
149 | ||
150 | /* void (*virtual_functions[0]) (); */ | |
151 | FIELD_NAME (*field) = "virtual_functions"; | |
e3506a9f | 152 | FIELD_TYPE (*field) = lookup_array_range_type (ptr_to_void_fn_type, 0, -1); |
7ed49443 JB |
153 | FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; |
154 | offset += TYPE_LENGTH (FIELD_TYPE (*field)); | |
155 | field++; | |
156 | ||
157 | /* We assumed in the allocation above that there were four fields. */ | |
3d499020 | 158 | gdb_assert (field == (field_list + 4)); |
7ed49443 | 159 | |
e9bb382b | 160 | t = arch_type (arch, TYPE_CODE_STRUCT, offset, NULL); |
7ed49443 JB |
161 | TYPE_NFIELDS (t) = field - field_list; |
162 | TYPE_FIELDS (t) = field_list; | |
163 | TYPE_TAG_NAME (t) = "gdb_gnu_v3_abi_vtable"; | |
e9bb382b | 164 | INIT_CPLUS_SPECIFIC (t); |
7ed49443 JB |
165 | |
166 | return t; | |
167 | } | |
168 | ||
169 | ||
ed09d7da KB |
170 | /* Return the ptrdiff_t type used in the vtable type. */ |
171 | static struct type * | |
172 | vtable_ptrdiff_type (struct gdbarch *gdbarch) | |
173 | { | |
174 | struct type *vtable_type = gdbarch_data (gdbarch, vtable_type_gdbarch_data); | |
175 | ||
176 | /* The "offset_to_top" field has the appropriate (ptrdiff_t) type. */ | |
177 | return TYPE_FIELD_TYPE (vtable_type, vtable_field_offset_to_top); | |
178 | } | |
179 | ||
7ed49443 JB |
180 | /* Return the offset from the start of the imaginary `struct |
181 | gdb_gnu_v3_abi_vtable' object to the vtable's "address point" | |
182 | (i.e., where objects' virtual table pointers point). */ | |
183 | static int | |
ad4820ab | 184 | vtable_address_point_offset (struct gdbarch *gdbarch) |
7ed49443 | 185 | { |
ad4820ab | 186 | struct type *vtable_type = gdbarch_data (gdbarch, vtable_type_gdbarch_data); |
7ed49443 JB |
187 | |
188 | return (TYPE_FIELD_BITPOS (vtable_type, vtable_field_virtual_functions) | |
189 | / TARGET_CHAR_BIT); | |
190 | } | |
191 | ||
192 | ||
d48cc9dd DJ |
193 | /* Determine whether structure TYPE is a dynamic class. Cache the |
194 | result. */ | |
195 | ||
196 | static int | |
197 | gnuv3_dynamic_class (struct type *type) | |
198 | { | |
199 | int fieldnum, fieldelem; | |
200 | ||
201 | if (TYPE_CPLUS_DYNAMIC (type)) | |
202 | return TYPE_CPLUS_DYNAMIC (type) == 1; | |
203 | ||
204 | ALLOCATE_CPLUS_STRUCT_TYPE (type); | |
205 | ||
206 | for (fieldnum = 0; fieldnum < TYPE_N_BASECLASSES (type); fieldnum++) | |
207 | if (BASETYPE_VIA_VIRTUAL (type, fieldnum) | |
208 | || gnuv3_dynamic_class (TYPE_FIELD_TYPE (type, fieldnum))) | |
209 | { | |
210 | TYPE_CPLUS_DYNAMIC (type) = 1; | |
211 | return 1; | |
212 | } | |
213 | ||
214 | for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++) | |
215 | for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum); | |
216 | fieldelem++) | |
217 | { | |
218 | struct fn_field *f = TYPE_FN_FIELDLIST1 (type, fieldnum); | |
219 | ||
220 | if (TYPE_FN_FIELD_VIRTUAL_P (f, fieldelem)) | |
221 | { | |
222 | TYPE_CPLUS_DYNAMIC (type) = 1; | |
223 | return 1; | |
224 | } | |
225 | } | |
226 | ||
227 | TYPE_CPLUS_DYNAMIC (type) = -1; | |
228 | return 0; | |
229 | } | |
230 | ||
231 | /* Find the vtable for a value of CONTAINER_TYPE located at | |
232 | CONTAINER_ADDR. Return a value of the correct vtable type for this | |
233 | architecture, or NULL if CONTAINER does not have a vtable. */ | |
234 | ||
235 | static struct value * | |
236 | gnuv3_get_vtable (struct gdbarch *gdbarch, | |
237 | struct type *container_type, CORE_ADDR container_addr) | |
238 | { | |
239 | struct type *vtable_type = gdbarch_data (gdbarch, | |
240 | vtable_type_gdbarch_data); | |
241 | struct type *vtable_pointer_type; | |
242 | struct value *vtable_pointer; | |
243 | CORE_ADDR vtable_address; | |
244 | ||
245 | /* If this type does not have a virtual table, don't read the first | |
246 | field. */ | |
247 | if (!gnuv3_dynamic_class (check_typedef (container_type))) | |
248 | return NULL; | |
249 | ||
250 | /* We do not consult the debug information to find the virtual table. | |
251 | The ABI specifies that it is always at offset zero in any class, | |
252 | and debug information may not represent it. | |
253 | ||
254 | We avoid using value_contents on principle, because the object might | |
255 | be large. */ | |
256 | ||
257 | /* Find the type "pointer to virtual table". */ | |
258 | vtable_pointer_type = lookup_pointer_type (vtable_type); | |
259 | ||
260 | /* Load it from the start of the class. */ | |
261 | vtable_pointer = value_at (vtable_pointer_type, container_addr); | |
262 | vtable_address = value_as_address (vtable_pointer); | |
263 | ||
264 | /* Correct it to point at the start of the virtual table, rather | |
265 | than the address point. */ | |
266 | return value_at_lazy (vtable_type, | |
267 | vtable_address - vtable_address_point_offset (gdbarch)); | |
268 | } | |
269 | ||
270 | ||
7ed49443 JB |
271 | static struct type * |
272 | gnuv3_rtti_type (struct value *value, | |
273 | int *full_p, int *top_p, int *using_enc_p) | |
274 | { | |
ad4820ab | 275 | struct gdbarch *gdbarch; |
df407dfe | 276 | struct type *values_type = check_typedef (value_type (value)); |
7ed49443 JB |
277 | struct value *vtable; |
278 | struct minimal_symbol *vtable_symbol; | |
279 | const char *vtable_symbol_name; | |
280 | const char *class_name; | |
7ed49443 JB |
281 | struct type *run_time_type; |
282 | LONGEST offset_to_top; | |
283 | ||
284 | /* We only have RTTI for class objects. */ | |
df407dfe | 285 | if (TYPE_CODE (values_type) != TYPE_CODE_CLASS) |
7ed49443 JB |
286 | return NULL; |
287 | ||
ad4820ab | 288 | /* Determine architecture. */ |
50810684 | 289 | gdbarch = get_type_arch (values_type); |
7ed49443 | 290 | |
21cfb3b6 DJ |
291 | if (using_enc_p) |
292 | *using_enc_p = 0; | |
293 | ||
d48cc9dd DJ |
294 | vtable = gnuv3_get_vtable (gdbarch, value_type (value), |
295 | value_as_address (value_addr (value))); | |
296 | if (vtable == NULL) | |
297 | return NULL; | |
298 | ||
7ed49443 JB |
299 | /* Find the linker symbol for this vtable. */ |
300 | vtable_symbol | |
42ae5230 | 301 | = lookup_minimal_symbol_by_pc (value_address (vtable) |
13c3b5f5 | 302 | + value_embedded_offset (vtable)); |
7ed49443 JB |
303 | if (! vtable_symbol) |
304 | return NULL; | |
305 | ||
306 | /* The symbol's demangled name should be something like "vtable for | |
307 | CLASS", where CLASS is the name of the run-time type of VALUE. | |
308 | If we didn't like this approach, we could instead look in the | |
309 | type_info object itself to get the class name. But this way | |
310 | should work just as well, and doesn't read target memory. */ | |
311 | vtable_symbol_name = SYMBOL_DEMANGLED_NAME (vtable_symbol); | |
98081e55 PB |
312 | if (vtable_symbol_name == NULL |
313 | || strncmp (vtable_symbol_name, "vtable for ", 11)) | |
f773fdbb | 314 | { |
8a3fe4f8 | 315 | warning (_("can't find linker symbol for virtual table for `%s' value"), |
df407dfe | 316 | TYPE_NAME (values_type)); |
f773fdbb | 317 | if (vtable_symbol_name) |
8a3fe4f8 | 318 | warning (_(" found `%s' instead"), vtable_symbol_name); |
f773fdbb JM |
319 | return NULL; |
320 | } | |
7ed49443 JB |
321 | class_name = vtable_symbol_name + 11; |
322 | ||
323 | /* Try to look up the class name as a type name. */ | |
362ff856 MC |
324 | /* FIXME: chastain/2003-11-26: block=NULL is bogus. See pr gdb/1465. */ |
325 | run_time_type = cp_lookup_rtti_type (class_name, NULL); | |
326 | if (run_time_type == NULL) | |
327 | return NULL; | |
7ed49443 JB |
328 | |
329 | /* Get the offset from VALUE to the top of the complete object. | |
330 | NOTE: this is the reverse of the meaning of *TOP_P. */ | |
331 | offset_to_top | |
332 | = value_as_long (value_field (vtable, vtable_field_offset_to_top)); | |
333 | ||
334 | if (full_p) | |
13c3b5f5 | 335 | *full_p = (- offset_to_top == value_embedded_offset (value) |
4754a64e | 336 | && (TYPE_LENGTH (value_enclosing_type (value)) |
7ed49443 JB |
337 | >= TYPE_LENGTH (run_time_type))); |
338 | if (top_p) | |
339 | *top_p = - offset_to_top; | |
7ed49443 JB |
340 | return run_time_type; |
341 | } | |
342 | ||
0d5de010 DJ |
343 | /* Return a function pointer for CONTAINER's VTABLE_INDEX'th virtual |
344 | function, of type FNTYPE. */ | |
7ed49443 | 345 | |
0d5de010 | 346 | static struct value * |
ad4820ab UW |
347 | gnuv3_get_virtual_fn (struct gdbarch *gdbarch, struct value *container, |
348 | struct type *fntype, int vtable_index) | |
0d5de010 | 349 | { |
d48cc9dd DJ |
350 | struct value *vtable, *vfn; |
351 | ||
352 | /* Every class with virtual functions must have a vtable. */ | |
353 | vtable = gnuv3_get_vtable (gdbarch, value_type (container), | |
354 | value_as_address (value_addr (container))); | |
355 | gdb_assert (vtable != NULL); | |
7ed49443 JB |
356 | |
357 | /* Fetch the appropriate function pointer from the vtable. */ | |
358 | vfn = value_subscript (value_field (vtable, vtable_field_virtual_functions), | |
2497b498 | 359 | vtable_index); |
7ed49443 | 360 | |
0d5de010 DJ |
361 | /* If this architecture uses function descriptors directly in the vtable, |
362 | then the address of the vtable entry is actually a "function pointer" | |
363 | (i.e. points to the descriptor). We don't need to scale the index | |
364 | by the size of a function descriptor; GCC does that before outputing | |
365 | debug information. */ | |
ad4820ab | 366 | if (gdbarch_vtable_function_descriptors (gdbarch)) |
0d5de010 | 367 | vfn = value_addr (vfn); |
7ed49443 | 368 | |
0d5de010 DJ |
369 | /* Cast the function pointer to the appropriate type. */ |
370 | vfn = value_cast (lookup_pointer_type (fntype), vfn); | |
76b79d6e | 371 | |
7ed49443 JB |
372 | return vfn; |
373 | } | |
374 | ||
0d5de010 DJ |
375 | /* GNU v3 implementation of value_virtual_fn_field. See cp-abi.h |
376 | for a description of the arguments. */ | |
377 | ||
378 | static struct value * | |
379 | gnuv3_virtual_fn_field (struct value **value_p, | |
380 | struct fn_field *f, int j, | |
381 | struct type *vfn_base, int offset) | |
382 | { | |
383 | struct type *values_type = check_typedef (value_type (*value_p)); | |
ad4820ab | 384 | struct gdbarch *gdbarch; |
0d5de010 DJ |
385 | |
386 | /* Some simple sanity checks. */ | |
387 | if (TYPE_CODE (values_type) != TYPE_CODE_CLASS) | |
388 | error (_("Only classes can have virtual functions.")); | |
389 | ||
ad4820ab | 390 | /* Determine architecture. */ |
50810684 | 391 | gdbarch = get_type_arch (values_type); |
ad4820ab | 392 | |
0d5de010 DJ |
393 | /* Cast our value to the base class which defines this virtual |
394 | function. This takes care of any necessary `this' | |
395 | adjustments. */ | |
396 | if (vfn_base != values_type) | |
397 | *value_p = value_cast (vfn_base, *value_p); | |
398 | ||
ad4820ab | 399 | return gnuv3_get_virtual_fn (gdbarch, *value_p, TYPE_FN_FIELD_TYPE (f, j), |
0d5de010 DJ |
400 | TYPE_FN_FIELD_VOFFSET (f, j)); |
401 | } | |
402 | ||
1514d34e DJ |
403 | /* Compute the offset of the baseclass which is |
404 | the INDEXth baseclass of class TYPE, | |
405 | for value at VALADDR (in host) at ADDRESS (in target). | |
406 | The result is the offset of the baseclass value relative | |
407 | to (the address of)(ARG) + OFFSET. | |
408 | ||
409 | -1 is returned on error. */ | |
b9362cc7 | 410 | static int |
96ce45ca | 411 | gnuv3_baseclass_offset (struct type *type, int index, const bfd_byte *valaddr, |
1514d34e DJ |
412 | CORE_ADDR address) |
413 | { | |
ad4820ab | 414 | struct gdbarch *gdbarch; |
ad4820ab | 415 | struct type *ptr_type; |
79d5b63a | 416 | struct value *vtable; |
2497b498 | 417 | struct value *vbase_array; |
1514d34e | 418 | long int cur_base_offset, base_offset; |
1514d34e | 419 | |
ad4820ab | 420 | /* Determine architecture. */ |
50810684 | 421 | gdbarch = get_type_arch (type); |
ad4820ab UW |
422 | ptr_type = builtin_type (gdbarch)->builtin_data_ptr; |
423 | ||
1514d34e DJ |
424 | /* If it isn't a virtual base, this is easy. The offset is in the |
425 | type definition. */ | |
426 | if (!BASETYPE_VIA_VIRTUAL (type, index)) | |
427 | return TYPE_BASECLASS_BITPOS (type, index) / 8; | |
428 | ||
429 | /* To access a virtual base, we need to use the vbase offset stored in | |
430 | our vtable. Recent GCC versions provide this information. If it isn't | |
431 | available, we could get what we needed from RTTI, or from drawing the | |
432 | complete inheritance graph based on the debug info. Neither is | |
433 | worthwhile. */ | |
434 | cur_base_offset = TYPE_BASECLASS_BITPOS (type, index) / 8; | |
ad4820ab | 435 | if (cur_base_offset >= - vtable_address_point_offset (gdbarch)) |
8a3fe4f8 | 436 | error (_("Expected a negative vbase offset (old compiler?)")); |
1514d34e | 437 | |
ad4820ab UW |
438 | cur_base_offset = cur_base_offset + vtable_address_point_offset (gdbarch); |
439 | if ((- cur_base_offset) % TYPE_LENGTH (ptr_type) != 0) | |
8a3fe4f8 | 440 | error (_("Misaligned vbase offset.")); |
ad4820ab | 441 | cur_base_offset = cur_base_offset / ((int) TYPE_LENGTH (ptr_type)); |
1514d34e | 442 | |
d48cc9dd DJ |
443 | vtable = gnuv3_get_vtable (gdbarch, type, address); |
444 | gdb_assert (vtable != NULL); | |
1514d34e | 445 | vbase_array = value_field (vtable, vtable_field_vcall_and_vbase_offsets); |
2497b498 | 446 | base_offset = value_as_long (value_subscript (vbase_array, cur_base_offset)); |
1514d34e DJ |
447 | return base_offset; |
448 | } | |
7ed49443 | 449 | |
0d5de010 DJ |
450 | /* Locate a virtual method in DOMAIN or its non-virtual base classes |
451 | which has virtual table index VOFFSET. The method has an associated | |
452 | "this" adjustment of ADJUSTMENT bytes. */ | |
453 | ||
2c0b251b | 454 | static const char * |
0d5de010 DJ |
455 | gnuv3_find_method_in (struct type *domain, CORE_ADDR voffset, |
456 | LONGEST adjustment) | |
457 | { | |
458 | int i; | |
459 | const char *physname; | |
460 | ||
461 | /* Search this class first. */ | |
462 | physname = NULL; | |
463 | if (adjustment == 0) | |
464 | { | |
465 | int len; | |
466 | ||
467 | len = TYPE_NFN_FIELDS (domain); | |
468 | for (i = 0; i < len; i++) | |
469 | { | |
470 | int len2, j; | |
471 | struct fn_field *f; | |
472 | ||
473 | f = TYPE_FN_FIELDLIST1 (domain, i); | |
474 | len2 = TYPE_FN_FIELDLIST_LENGTH (domain, i); | |
475 | ||
476 | check_stub_method_group (domain, i); | |
477 | for (j = 0; j < len2; j++) | |
478 | if (TYPE_FN_FIELD_VOFFSET (f, j) == voffset) | |
479 | return TYPE_FN_FIELD_PHYSNAME (f, j); | |
480 | } | |
481 | } | |
482 | ||
483 | /* Next search non-virtual bases. If it's in a virtual base, | |
484 | we're out of luck. */ | |
485 | for (i = 0; i < TYPE_N_BASECLASSES (domain); i++) | |
486 | { | |
487 | int pos; | |
488 | struct type *basetype; | |
489 | ||
490 | if (BASETYPE_VIA_VIRTUAL (domain, i)) | |
491 | continue; | |
492 | ||
493 | pos = TYPE_BASECLASS_BITPOS (domain, i) / 8; | |
494 | basetype = TYPE_FIELD_TYPE (domain, i); | |
495 | /* Recurse with a modified adjustment. We don't need to adjust | |
496 | voffset. */ | |
497 | if (adjustment >= pos && adjustment < pos + TYPE_LENGTH (basetype)) | |
498 | return gnuv3_find_method_in (basetype, voffset, adjustment - pos); | |
499 | } | |
500 | ||
501 | return NULL; | |
502 | } | |
503 | ||
fead6908 UW |
504 | /* Decode GNU v3 method pointer. */ |
505 | ||
506 | static int | |
ad4820ab UW |
507 | gnuv3_decode_method_ptr (struct gdbarch *gdbarch, |
508 | const gdb_byte *contents, | |
fead6908 UW |
509 | CORE_ADDR *value_p, |
510 | LONGEST *adjustment_p) | |
511 | { | |
ad4820ab | 512 | struct type *funcptr_type = builtin_type (gdbarch)->builtin_func_ptr; |
ed09d7da | 513 | struct type *offset_type = vtable_ptrdiff_type (gdbarch); |
e17a4113 | 514 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
fead6908 UW |
515 | CORE_ADDR ptr_value; |
516 | LONGEST voffset, adjustment; | |
517 | int vbit; | |
518 | ||
519 | /* Extract the pointer to member. The first element is either a pointer | |
520 | or a vtable offset. For pointers, we need to use extract_typed_address | |
521 | to allow the back-end to convert the pointer to a GDB address -- but | |
522 | vtable offsets we must handle as integers. At this point, we do not | |
523 | yet know which case we have, so we extract the value under both | |
524 | interpretations and choose the right one later on. */ | |
525 | ptr_value = extract_typed_address (contents, funcptr_type); | |
e17a4113 UW |
526 | voffset = extract_signed_integer (contents, |
527 | TYPE_LENGTH (funcptr_type), byte_order); | |
fead6908 | 528 | contents += TYPE_LENGTH (funcptr_type); |
e17a4113 UW |
529 | adjustment = extract_signed_integer (contents, |
530 | TYPE_LENGTH (offset_type), byte_order); | |
fead6908 | 531 | |
ad4820ab | 532 | if (!gdbarch_vbit_in_delta (gdbarch)) |
fead6908 UW |
533 | { |
534 | vbit = voffset & 1; | |
535 | voffset = voffset ^ vbit; | |
536 | } | |
537 | else | |
538 | { | |
539 | vbit = adjustment & 1; | |
540 | adjustment = adjustment >> 1; | |
541 | } | |
542 | ||
543 | *value_p = vbit? voffset : ptr_value; | |
544 | *adjustment_p = adjustment; | |
545 | return vbit; | |
546 | } | |
547 | ||
0d5de010 DJ |
548 | /* GNU v3 implementation of cplus_print_method_ptr. */ |
549 | ||
550 | static void | |
551 | gnuv3_print_method_ptr (const gdb_byte *contents, | |
552 | struct type *type, | |
553 | struct ui_file *stream) | |
554 | { | |
ad4820ab | 555 | struct type *domain = TYPE_DOMAIN_TYPE (type); |
50810684 | 556 | struct gdbarch *gdbarch = get_type_arch (domain); |
0d5de010 DJ |
557 | CORE_ADDR ptr_value; |
558 | LONGEST adjustment; | |
0d5de010 DJ |
559 | int vbit; |
560 | ||
0d5de010 | 561 | /* Extract the pointer to member. */ |
ad4820ab | 562 | vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment); |
0d5de010 DJ |
563 | |
564 | /* Check for NULL. */ | |
565 | if (ptr_value == 0 && vbit == 0) | |
566 | { | |
567 | fprintf_filtered (stream, "NULL"); | |
568 | return; | |
569 | } | |
570 | ||
571 | /* Search for a virtual method. */ | |
572 | if (vbit) | |
573 | { | |
574 | CORE_ADDR voffset; | |
575 | const char *physname; | |
576 | ||
577 | /* It's a virtual table offset, maybe in this class. Search | |
578 | for a field with the correct vtable offset. First convert it | |
579 | to an index, as used in TYPE_FN_FIELD_VOFFSET. */ | |
ed09d7da | 580 | voffset = ptr_value / TYPE_LENGTH (vtable_ptrdiff_type (gdbarch)); |
0d5de010 DJ |
581 | |
582 | physname = gnuv3_find_method_in (domain, voffset, adjustment); | |
583 | ||
584 | /* If we found a method, print that. We don't bother to disambiguate | |
585 | possible paths to the method based on the adjustment. */ | |
586 | if (physname) | |
587 | { | |
588 | char *demangled_name = cplus_demangle (physname, | |
589 | DMGL_ANSI | DMGL_PARAMS); | |
590 | if (demangled_name != NULL) | |
591 | { | |
592 | fprintf_filtered (stream, "&virtual "); | |
593 | fputs_filtered (demangled_name, stream); | |
594 | xfree (demangled_name); | |
595 | return; | |
596 | } | |
597 | } | |
598 | } | |
599 | ||
600 | /* We didn't find it; print the raw data. */ | |
601 | if (vbit) | |
602 | { | |
603 | fprintf_filtered (stream, "&virtual table offset "); | |
604 | print_longest (stream, 'd', 1, ptr_value); | |
605 | } | |
606 | else | |
5af949e3 | 607 | print_address_demangle (gdbarch, ptr_value, stream, demangle); |
0d5de010 DJ |
608 | |
609 | if (adjustment) | |
610 | { | |
611 | fprintf_filtered (stream, ", this adjustment "); | |
612 | print_longest (stream, 'd', 1, adjustment); | |
613 | } | |
614 | } | |
615 | ||
616 | /* GNU v3 implementation of cplus_method_ptr_size. */ | |
617 | ||
618 | static int | |
ad4820ab | 619 | gnuv3_method_ptr_size (struct type *type) |
0d5de010 | 620 | { |
ad4820ab | 621 | struct type *domain_type = check_typedef (TYPE_DOMAIN_TYPE (type)); |
50810684 | 622 | struct gdbarch *gdbarch = get_type_arch (domain_type); |
ad4820ab | 623 | return 2 * TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr); |
0d5de010 DJ |
624 | } |
625 | ||
626 | /* GNU v3 implementation of cplus_make_method_ptr. */ | |
627 | ||
628 | static void | |
ad4820ab UW |
629 | gnuv3_make_method_ptr (struct type *type, gdb_byte *contents, |
630 | CORE_ADDR value, int is_virtual) | |
0d5de010 | 631 | { |
ad4820ab | 632 | struct type *domain_type = check_typedef (TYPE_DOMAIN_TYPE (type)); |
50810684 | 633 | struct gdbarch *gdbarch = get_type_arch (domain_type); |
ad4820ab | 634 | int size = TYPE_LENGTH (builtin_type (gdbarch)->builtin_data_ptr); |
e17a4113 | 635 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
0d5de010 DJ |
636 | |
637 | /* FIXME drow/2006-12-24: The adjustment of "this" is currently | |
638 | always zero, since the method pointer is of the correct type. | |
639 | But if the method pointer came from a base class, this is | |
640 | incorrect - it should be the offset to the base. The best | |
641 | fix might be to create the pointer to member pointing at the | |
642 | base class and cast it to the derived class, but that requires | |
643 | support for adjusting pointers to members when casting them - | |
644 | not currently supported by GDB. */ | |
645 | ||
ad4820ab | 646 | if (!gdbarch_vbit_in_delta (gdbarch)) |
0d5de010 | 647 | { |
e17a4113 UW |
648 | store_unsigned_integer (contents, size, byte_order, value | is_virtual); |
649 | store_unsigned_integer (contents + size, size, byte_order, 0); | |
0d5de010 DJ |
650 | } |
651 | else | |
652 | { | |
e17a4113 UW |
653 | store_unsigned_integer (contents, size, byte_order, value); |
654 | store_unsigned_integer (contents + size, size, byte_order, is_virtual); | |
0d5de010 DJ |
655 | } |
656 | } | |
657 | ||
658 | /* GNU v3 implementation of cplus_method_ptr_to_value. */ | |
659 | ||
660 | static struct value * | |
661 | gnuv3_method_ptr_to_value (struct value **this_p, struct value *method_ptr) | |
662 | { | |
ad4820ab | 663 | struct gdbarch *gdbarch; |
0d5de010 DJ |
664 | const gdb_byte *contents = value_contents (method_ptr); |
665 | CORE_ADDR ptr_value; | |
ad4820ab | 666 | struct type *domain_type, *final_type, *method_type; |
0d5de010 | 667 | LONGEST adjustment; |
0d5de010 DJ |
668 | int vbit; |
669 | ||
ad4820ab UW |
670 | domain_type = TYPE_DOMAIN_TYPE (check_typedef (value_type (method_ptr))); |
671 | final_type = lookup_pointer_type (domain_type); | |
0d5de010 DJ |
672 | |
673 | method_type = TYPE_TARGET_TYPE (check_typedef (value_type (method_ptr))); | |
674 | ||
fead6908 | 675 | /* Extract the pointer to member. */ |
50810684 | 676 | gdbarch = get_type_arch (domain_type); |
ad4820ab | 677 | vbit = gnuv3_decode_method_ptr (gdbarch, contents, &ptr_value, &adjustment); |
0d5de010 DJ |
678 | |
679 | /* First convert THIS to match the containing type of the pointer to | |
680 | member. This cast may adjust the value of THIS. */ | |
681 | *this_p = value_cast (final_type, *this_p); | |
682 | ||
683 | /* Then apply whatever adjustment is necessary. This creates a somewhat | |
684 | strange pointer: it claims to have type FINAL_TYPE, but in fact it | |
685 | might not be a valid FINAL_TYPE. For instance, it might be a | |
686 | base class of FINAL_TYPE. And if it's not the primary base class, | |
687 | then printing it out as a FINAL_TYPE object would produce some pretty | |
688 | garbage. | |
689 | ||
690 | But we don't really know the type of the first argument in | |
691 | METHOD_TYPE either, which is why this happens. We can't | |
692 | dereference this later as a FINAL_TYPE, but once we arrive in the | |
693 | called method we'll have debugging information for the type of | |
694 | "this" - and that'll match the value we produce here. | |
695 | ||
696 | You can provoke this case by casting a Base::* to a Derived::*, for | |
697 | instance. */ | |
ad4820ab | 698 | *this_p = value_cast (builtin_type (gdbarch)->builtin_data_ptr, *this_p); |
2497b498 | 699 | *this_p = value_ptradd (*this_p, adjustment); |
0d5de010 DJ |
700 | *this_p = value_cast (final_type, *this_p); |
701 | ||
702 | if (vbit) | |
703 | { | |
ad4820ab | 704 | LONGEST voffset; |
ed09d7da | 705 | voffset = ptr_value / TYPE_LENGTH (vtable_ptrdiff_type (gdbarch)); |
ad4820ab UW |
706 | return gnuv3_get_virtual_fn (gdbarch, value_ind (*this_p), |
707 | method_type, voffset); | |
0d5de010 DJ |
708 | } |
709 | else | |
710 | return value_from_pointer (lookup_pointer_type (method_type), ptr_value); | |
711 | } | |
712 | ||
b18be20d DJ |
713 | /* Determine if we are currently in a C++ thunk. If so, get the address |
714 | of the routine we are thunking to and continue to there instead. */ | |
715 | ||
716 | static CORE_ADDR | |
52f729a7 | 717 | gnuv3_skip_trampoline (struct frame_info *frame, CORE_ADDR stop_pc) |
b18be20d DJ |
718 | { |
719 | CORE_ADDR real_stop_pc, method_stop_pc; | |
9970f04b | 720 | struct gdbarch *gdbarch = get_frame_arch (frame); |
b18be20d DJ |
721 | struct minimal_symbol *thunk_sym, *fn_sym; |
722 | struct obj_section *section; | |
723 | char *thunk_name, *fn_name; | |
724 | ||
9970f04b | 725 | real_stop_pc = gdbarch_skip_trampoline_code (gdbarch, frame, stop_pc); |
b18be20d DJ |
726 | if (real_stop_pc == 0) |
727 | real_stop_pc = stop_pc; | |
728 | ||
729 | /* Find the linker symbol for this potential thunk. */ | |
730 | thunk_sym = lookup_minimal_symbol_by_pc (real_stop_pc); | |
731 | section = find_pc_section (real_stop_pc); | |
732 | if (thunk_sym == NULL || section == NULL) | |
733 | return 0; | |
734 | ||
735 | /* The symbol's demangled name should be something like "virtual | |
736 | thunk to FUNCTION", where FUNCTION is the name of the function | |
737 | being thunked to. */ | |
738 | thunk_name = SYMBOL_DEMANGLED_NAME (thunk_sym); | |
739 | if (thunk_name == NULL || strstr (thunk_name, " thunk to ") == NULL) | |
740 | return 0; | |
741 | ||
742 | fn_name = strstr (thunk_name, " thunk to ") + strlen (" thunk to "); | |
743 | fn_sym = lookup_minimal_symbol (fn_name, NULL, section->objfile); | |
744 | if (fn_sym == NULL) | |
745 | return 0; | |
746 | ||
747 | method_stop_pc = SYMBOL_VALUE_ADDRESS (fn_sym); | |
e76f05fa | 748 | real_stop_pc = gdbarch_skip_trampoline_code |
9970f04b | 749 | (gdbarch, frame, method_stop_pc); |
b18be20d DJ |
750 | if (real_stop_pc == 0) |
751 | real_stop_pc = method_stop_pc; | |
752 | ||
753 | return real_stop_pc; | |
754 | } | |
755 | ||
41f1b697 DJ |
756 | /* Return nonzero if a type should be passed by reference. |
757 | ||
758 | The rule in the v3 ABI document comes from section 3.1.1. If the | |
759 | type has a non-trivial copy constructor or destructor, then the | |
760 | caller must make a copy (by calling the copy constructor if there | |
761 | is one or perform the copy itself otherwise), pass the address of | |
762 | the copy, and then destroy the temporary (if necessary). | |
763 | ||
764 | For return values with non-trivial copy constructors or | |
765 | destructors, space will be allocated in the caller, and a pointer | |
766 | will be passed as the first argument (preceding "this"). | |
767 | ||
768 | We don't have a bulletproof mechanism for determining whether a | |
769 | constructor or destructor is trivial. For GCC and DWARF2 debug | |
770 | information, we can check the artificial flag. | |
771 | ||
772 | We don't do anything with the constructors or destructors, | |
773 | but we have to get the argument passing right anyway. */ | |
774 | static int | |
775 | gnuv3_pass_by_reference (struct type *type) | |
776 | { | |
777 | int fieldnum, fieldelem; | |
778 | ||
779 | CHECK_TYPEDEF (type); | |
780 | ||
781 | /* We're only interested in things that can have methods. */ | |
782 | if (TYPE_CODE (type) != TYPE_CODE_STRUCT | |
783 | && TYPE_CODE (type) != TYPE_CODE_CLASS | |
784 | && TYPE_CODE (type) != TYPE_CODE_UNION) | |
785 | return 0; | |
786 | ||
787 | for (fieldnum = 0; fieldnum < TYPE_NFN_FIELDS (type); fieldnum++) | |
788 | for (fieldelem = 0; fieldelem < TYPE_FN_FIELDLIST_LENGTH (type, fieldnum); | |
789 | fieldelem++) | |
790 | { | |
791 | struct fn_field *fn = TYPE_FN_FIELDLIST1 (type, fieldnum); | |
792 | char *name = TYPE_FN_FIELDLIST_NAME (type, fieldnum); | |
793 | struct type *fieldtype = TYPE_FN_FIELD_TYPE (fn, fieldelem); | |
794 | ||
795 | /* If this function is marked as artificial, it is compiler-generated, | |
796 | and we assume it is trivial. */ | |
797 | if (TYPE_FN_FIELD_ARTIFICIAL (fn, fieldelem)) | |
798 | continue; | |
799 | ||
800 | /* If we've found a destructor, we must pass this by reference. */ | |
801 | if (name[0] == '~') | |
802 | return 1; | |
803 | ||
804 | /* If the mangled name of this method doesn't indicate that it | |
805 | is a constructor, we're not interested. | |
806 | ||
807 | FIXME drow/2007-09-23: We could do this using the name of | |
808 | the method and the name of the class instead of dealing | |
809 | with the mangled name. We don't have a convenient function | |
810 | to strip off both leading scope qualifiers and trailing | |
811 | template arguments yet. */ | |
812 | if (!is_constructor_name (TYPE_FN_FIELD_PHYSNAME (fn, fieldelem))) | |
813 | continue; | |
814 | ||
815 | /* If this method takes two arguments, and the second argument is | |
816 | a reference to this class, then it is a copy constructor. */ | |
817 | if (TYPE_NFIELDS (fieldtype) == 2 | |
818 | && TYPE_CODE (TYPE_FIELD_TYPE (fieldtype, 1)) == TYPE_CODE_REF | |
819 | && check_typedef (TYPE_TARGET_TYPE (TYPE_FIELD_TYPE (fieldtype, 1))) == type) | |
820 | return 1; | |
821 | } | |
822 | ||
823 | /* Even if all the constructors and destructors were artificial, one | |
824 | of them may have invoked a non-artificial constructor or | |
825 | destructor in a base class. If any base class needs to be passed | |
826 | by reference, so does this class. Similarly for members, which | |
827 | are constructed whenever this class is. We do not need to worry | |
828 | about recursive loops here, since we are only looking at members | |
829 | of complete class type. */ | |
830 | for (fieldnum = 0; fieldnum < TYPE_NFIELDS (type); fieldnum++) | |
831 | if (gnuv3_pass_by_reference (TYPE_FIELD_TYPE (type, fieldnum))) | |
832 | return 1; | |
833 | ||
834 | return 0; | |
835 | } | |
836 | ||
7ed49443 JB |
837 | static void |
838 | init_gnuv3_ops (void) | |
839 | { | |
030f20e1 | 840 | vtable_type_gdbarch_data = gdbarch_data_register_post_init (build_gdb_vtable_type); |
7ed49443 JB |
841 | |
842 | gnu_v3_abi_ops.shortname = "gnu-v3"; | |
843 | gnu_v3_abi_ops.longname = "GNU G++ Version 3 ABI"; | |
844 | gnu_v3_abi_ops.doc = "G++ Version 3 ABI"; | |
358777b0 EZ |
845 | gnu_v3_abi_ops.is_destructor_name = |
846 | (enum dtor_kinds (*) (const char *))is_gnu_v3_mangled_dtor; | |
847 | gnu_v3_abi_ops.is_constructor_name = | |
848 | (enum ctor_kinds (*) (const char *))is_gnu_v3_mangled_ctor; | |
7ed49443 JB |
849 | gnu_v3_abi_ops.is_vtable_name = gnuv3_is_vtable_name; |
850 | gnu_v3_abi_ops.is_operator_name = gnuv3_is_operator_name; | |
851 | gnu_v3_abi_ops.rtti_type = gnuv3_rtti_type; | |
852 | gnu_v3_abi_ops.virtual_fn_field = gnuv3_virtual_fn_field; | |
1514d34e | 853 | gnu_v3_abi_ops.baseclass_offset = gnuv3_baseclass_offset; |
0d5de010 DJ |
854 | gnu_v3_abi_ops.print_method_ptr = gnuv3_print_method_ptr; |
855 | gnu_v3_abi_ops.method_ptr_size = gnuv3_method_ptr_size; | |
856 | gnu_v3_abi_ops.make_method_ptr = gnuv3_make_method_ptr; | |
857 | gnu_v3_abi_ops.method_ptr_to_value = gnuv3_method_ptr_to_value; | |
b18be20d | 858 | gnu_v3_abi_ops.skip_trampoline = gnuv3_skip_trampoline; |
41f1b697 | 859 | gnu_v3_abi_ops.pass_by_reference = gnuv3_pass_by_reference; |
7ed49443 JB |
860 | } |
861 | ||
b9362cc7 | 862 | extern initialize_file_ftype _initialize_gnu_v3_abi; /* -Wmissing-prototypes */ |
7ed49443 JB |
863 | |
864 | void | |
865 | _initialize_gnu_v3_abi (void) | |
866 | { | |
867 | init_gnuv3_ops (); | |
868 | ||
fe1f4a5e | 869 | register_cp_abi (&gnu_v3_abi_ops); |
7ed49443 | 870 | } |